Cast in situ deck construction and core unit for use therein

ABSTRACT

A core unit for use in constructing a cast in situ deck or the like is provided which is formed from sheet material, such as laminated paperboard. The core unit includes an elongated top panel reinforced at one end, side panels depending outwardly from opposite sides of said top panels, and reinforced base panels extending laterally outwardly from the lower edges of the side panels. An elongated transversely extending reinforcing member spans the distance between the base panels and has the ends thereof projecting beyond the side panels. The projecting ends of the reinforcing member are adapted to interlock with an end of a second core unit of like construction arranged in overlapping end-to-end relation therewith.

United States Patent 1191 Estes et a1.

541 CAST IN srru DECK CONSTRUCTION AND CORE UNIT FOR USE THERE IN 22 Filed: July 29, 1971 21 App1.No.: 167,183

[52] US. Cl. ..52/9 8, 52/329, 52/577 [51] Int. Cl ..E04h1/16, E04b 5/36 [58] '.Field ofSearch ..52/576, 577, 329, 330, 477',

1 51 Jan. 9, 1973 1,750,760 3 1930 Kepple ..249 2sx 2,734,250 2/1956 Thompson ..249/28 FOREIGN PATENTS OR APPLICATIONS Primary Examiner-John Murtagh Attorney-Albert H.'Pendleton, et al 57 ABSTRACT A core unit for use in constructing a cast in situ deck or the like is provided which is formed from sheet material, such as laminated paperboard. The core unit includes an elongated top panel reinforced at one end, side panels depending outwardly from opposite sides of said top panels, and reinforced base panelsextending laterally outwardly from the lower edges of the side panels. An elongated transversely extending reinforcing member spans the distance between the base panels and has the ends thereof projecting beyond the side panels. The projecting ends of the reinforcing member are adapted to interlock with an end of a second core unit of like construction arranged-in overlapping end-to-end relation therewith.

1901511115, 8 Drawing Figures 11/1966 France ..52 577 Pmmaum 9mm 3,708,929

SHEET 2 [IF 2 CAST IN SITU DECK CONSTRUCTION AND CORE UNIT FOR USE THEREIN BACKGROUND OF THE INVENTION In the construction of many types of building it has been fou'nd'desirable both from a structural standpoint as well as a cost standpoint to utilize castin situ deck constructions either for floors or roofs. Where the building in question is ajmulti-story structure, floors of this type are desirable because they are vibration-free, provide a good sound and fire barrier, permit ready relocationof interior partitions, and alsoreduce labor and material costs. Similar advantages are applicable, as well, to cast in situ roof deck constructions.

' I-Ieretofore, various forms have been utilized for constructing' such decks; however, such forms oftentimes have a high initial cost, are awkward and difficult to handle, and/or require the utilization of numerous special tools. Furthermore, such prior forms frequently have poor load-bearing characteristics making it hazardous for persons to walk on the forms prior to the hardening of concrete or other cementitious material distributed thereover. With prior forms, it was often difficult and awkward to install structural members such as duct work, electrical conduitsfpldmbing pipes, etc'., if they were to extend cross-wise of the forms because a substantial amount of time and labor was expended in sawing and cutting out portions of the forms so as to accommodate said members.

SUMMARY OF THE INVENTION pens'ate for structural and dimensional variations that oftentimes occur during construction ofa building.

Further and additional objects will appear from the description, accompanying drawings, and appended claims.

In accordancewith one embodiment of the invention a form (hereafter referred to as a core unit) is provide for use in a cast in situ deck construction. The unit includes a top panel, side panels depending outwardly from opposite side edges of the top panel, and reinforced base panels extending laterally outwardly from the lower ends of the side panels. The base panels are adapted to rest upon and be supported by shoulders formed on stationary elongated support members arrangedhorizontally in uniformly spaced substantially parallel relation. One end of the top and corresponding ends of the side panels are provided with an inwardly projecting reinforcing flange. The top, side, and base panels and at the reinforcing flange are formed from heavy duty sheet material (e.g. laminated paperboard) which is treated so as to be moisture resistant. The blankis of sufficient thickness and composition so as to withstand'heavy transverse and compressive Ioadsand An elongated transversely extending reinforcing element s'pans'the distance between the base' panels and has the opposite ends thereof extending beyond the side panels and upwardly from the base panels. The ends of the'reinforcing elements are adapted to interlockingly engage theopposite end of a like core unit arranged in end-to-end relation therewith.

DESCRIPTION For a more complete understanding of the invention reference should be made to the drawings wherein:

FIG. 1 is a fragmentary perspective top view partially in-section of one form of the improved deck construction.

FIG. 2 is a fragmentary perspective side view of the improved deck construction prior to the cementitious material being distributed over the core units, and

showing the latter interlocked in'end-to-end partially overlapping relation.

FIG. 3 is a fragmentary perspective end'view of the structure shown in FIG. 2.

FIG. 4 is a perspective bottom view of one of the core units shown in FIG. 1. a I j FIG. 5 is a perspective bottom view similar to FIG. 4, but showing the" knockout areas formed in the side panels. v

FIG. 6 is a perspective end view of a plurality of the core units arranged in a compact nested relation suitais shown which may be used as a floor deck in a multistory building or as a roof deck in such a building. A 7

portion of the stratum 11 of cementitious material (e.g. concrete) utilized in the deck construction has been cut away so as to expose the various structural components utilized in said deck construction. In addition to the stratum 11, the construction 10 includes a plurality of elongated, horizontally disposed supports 12 (often referred to -as purlins) arranged in uniformly spaced, parallel relation. Such supports may be of the truss tee type disclosed in U. S. Pat. No. 3,456,415. The length of the supports will depend upon the spacing between load-bearing walls which delimit the area to be covered by the deck. The ends of the supports are anchored to the load-bearing walls, not shown, by any conventional means. I i v Disposed intermediate the supports and supported thereby, are a plurality of core units 13 which are arranged so as to form one row of Core units between each pair of adjacent supports 12. Once the entire area is covered with the parallel supports 12 and the rows of core' units 13, the stratum 11 is formed by pumping, belting, chuting,,or bucketing the cementitious material while in a flowable state over the upper exposed suryet, is sufficiently lightweight so that it can be readily manually handled for fitting into place.

faces of the core units andsupports until a predetermined thickness (e.g. l to 2 inches) of the material is disposed above the uppermost portions of the-core units. Y

Prior to distributing the cementitious material over the core units and supports, it may be desirable to shore up the supports by suitable scaffolding S, see FIG. 3,

particularly if the-deck is to have a substantial span.

Each support 12 is provided with a'central upwardly projecting strut 12a which mayv be of a chordal con struction. Extending laterally outwardly in opposite directionsfromthe bottom portionof the strut are shoulders l2bupon which the core units rest when'assembled with the supports 12. The shoulders of'th'e supports are disposed in'a'horizontal plane. The supports are-normally disposed on 24inch centers.

construction when said cor e units are in assembled relation, see FIG. 2. Because the slots 17 are spaced inwardly from the larger end B of the second core unit,

' the larger end partially overlaps the narrower end A of Each core unit 13 is of like construction and, as seen 7 in FIGS.-

and 5, includes an elongated substantially rectangular top panel 14, which is adapted to be horizontally disposed when thc'unit is,ass embledwith the supports. One end A of the panel is slightly narrower than the other end B so that the elongated side edges of the panel 14 will diverge slightly from end A.

Foldably connected to-the elongated side edges of formed in the'lower edge of each side panel at the tern minusof the foreshortened-end of the base panel. The slots 17 are transversely aligned with. respect to one another and their function will be discussed more fully hereafter;

.'Affixed to th'e'underside of the base panels l6 and.

substantially coextensive therewith are elongated, thin,

substantially inflexible reinforcingstrips 18, The strips 18 are adapted toengage the shoulders of thesupports 12 when the deckis constructed..;The strips 18 prevent bowing of the side panels 16- when the latter are sub jected tov'load forces. The width of each strip 18 may be slightly greater than the width of each basepanel 16 so the previously laid core unit. Thus, the narrow end of the'fir'stcore unit reinforces and supports the larger end of the second core unit, when said units are in assembled relation. Besides providing a means for interlocking successive core units of 'a row, the member 23 serves to retain the side panels'ls in relatively fixed positions, notwithstanding that said core unit is subjected to substantial compressive and transverse loads.

As seen in'FlGS. 2 and '5, the side panels 15 of each core unit are provided with one or more knockout areas 24. Corresponding areas in the side panels are transversely aligned with one anothenThe size, shape,

that the inner edge 18a of the strip projects beyond the edge of the support shoulder 12b, seeFIGS. l and2;

At the narrow edge'Aof the top panel 14 and the corresponding edges of the side panels 15 are 'foldably connected flaps 20 and '21, respectively, which are adapted toco operate with one another to form 'an inwardly projectingreinforcing flange F, see'FlG. 1. To the inner face of flap 20 is secured an elongated,'n arrow, substantially inflexible slat-22 (see FIG. 5 which is substantially coextensive with'flap 20. :Theends of the slat are affixed'byany suitable fastening means to the overlapping portions of the flaps 20 and 21. Slat 22 serves to-resistsagging' of the top panel 14 when the latter is subjected to loads caused by the stratum ll itself duringsetup thereof'or by theweight 'of workersor equipment used to distribute the flowable cementitious material over the core units;

Disposed in spaced, substantially parallel relation beneathpslat 22 and secured to the outer surface of flaps 21 is an elongated, narrow, inflexible reinforcing member 23. Member 23 spans the distance between the side panels 15 and has the ends 23a thereof extending beyond the side panels 15.,The ends 23a project upwardly from the plane of base panelsv 16 and are adaptedto berinterlockingly accommodated within the 7 slots 17 formedin the end of a second core unit of like number, and location of the areas may vary, if desired, from that shown. Each area, however, is defined by a pair of spaced concentricallyarrang'ed lines 25 and 26,

' see FIG. 5. Line 25 delimits asmaller area than-line'26 and is formed on the inner surface of the side panel, that is to say the, surface which] faces angularly downwardly whenthe core unit is in place between ad- I jacent. supports 12, Line 26, on thefothe'r hand, is formed, on the outeror upwardly facing surface of the same'side panel. The lines 25 and 26, in both instances, may be cuts'or perforations which penetrate the side panel a'distance less than the total thickness of the 1 panel. The size differential between theareas delimited by the linesmay be such that a margin of approximately one half inchencompasses'the smaller area. Because the smaller line 25 is formed'on the inner surface. ofthe side panel 15, the opening in the side panel can be readily produced by-strikingthe area 24 delimited by line 25-with an outwardly directed blow from a hammer or 'similar object. Onthe other hand, 'themargin encompassing the smaller area strongly resists inward deflection or inward knocking out of area 24.

Obviously, the outward'knoc'king out of area 24 is.

undertaken before the flowable cementitious material is deposited over the core units. Which-core units in the rows will have knockout openings formed thereinwill depend upon the location of the transversestructural members-Keg. ducts, conduits, or plumbing pipes, etc.)', not shown, in the space covered by the deck construction. The shape and'size of the-knockout openings in the side-panels 15 will conform substantially to the cross-sectional shape of standard size ducts and the likepwhere' the knockout openings need to-be enla'rged, this can readily be'accomplished-by utilizing either a hand or power saw'. The duct work, conduit, or piping; which runs parallel to the rows of core units may be readily positioned in the voids ortroffers V, see FIG. 1', formed byfithe top and side panels of the core A unit.

The 'core'units remain in place after thestraturn ll has hardened. The thicknessof the sheet materialforming the topand side panels and flaps of the core units is sufficient to hold hanger screws orjthe like utilized in l8aof reinforcing stripsl8 may provide a convenient means for attaching ceiling or acoustical ,tiles or the like to the underside of the deck construction.

The stratum 1 1 normally will be approximately twelve inches thick in the areal between adjacent rows of core units and will be approximately 1% to 2 inches thick in the area II disposed over the top panel 14 of each core unit. The relative thickness of the areas I and II is shown somewhat distorted in FIG. 1. Because the center portion 12a of the truss tee supports 12 are embedded within the stratum portions I, said portions are reinforced thereby. As aforementioned, the center portion. of the support is preferably of chordal construction thereby enabling the cementitio'us material to become keyedto the support.

To facilitate the erection of the improved deck con: struction, it may be desirable to utilize a starter unit 29 having the components thereof shown in partially ex- .27 which conforms substantially to the cross-sectional shape of the void V formed in the underside of the starter unit. Secured to the exposed surface of partition 27and alongthe bottom portion thereof is an elongated narrow', substantially inflexible member 28 which is of the same size and shape as member 23 formed on the narrow end of'the. core'unit'13. The ends 28a of member 28 are adapted to rest upon the shoulders 12b of adjacent supports 12. The projecting ends 23a of reinforcing member 23 disposed at the opposite end of the starter unit are adapted-to interlock with the slots 17 formed adjacent the large end B of the first laid core unitof the row. I

' Prior to the last core unit of a row being laid or put in place between the supports, a cover piece 30, see FIG. 8, is, mounted'on the narrow end A of the core unit. Piece 30 may be formed of suitable imperforate fiberboard and has a'configuration approximating that of the narrow end of the core unit; except, along the upperedge of the piece there is provided-a pair of laterally spaced slits 31 which define the end limits of a tongue 32. The tongueis adapted to be offset inwardly so as to cause the upper edge of piece 30 to partially 'straddle the depending flap 20 and reinforcing slat 22 comprising a part of the core unit narrow end A.

second support (purlin) is placed at approximately a 2 foot center and in parallel relation with respect to the tending shoulders of the supports. Therow of core units is commenced by initially'placing a starter unit 29 adjacent one end of the supports. The last core unit of the row has a cover piece 30 placed over the narrow end of the core unit before it is put. in place. i

In determining the number of core units to be used in forming a row, it is recommended that the installer initially measure the span length and then divide said length into as many 2foot segments as possible. For example, if the span length 21 feet '5 inches, there would be ten foot segments or 20 feet with a remainder of 1 foot, 5 inches. The starter unit 29 would then be cut from a core unit so as to have a longitudinal dimension of 1 foot, 5 inches from end A and then par tition 27 is securedin place at the cut end. I

Once the row of core units is completed, the unanchored second support isjsnugged in against the row of core units so that all of the corresponding reinforced base panels of the core units are resting securely on-the support shoulder. The ends of the second support are then anchored to the load-bearing walls, not shown. The foregoing procedure is repeated until the area involved is completely covered. Once all of the core units and supports are in place; the'transversely extending heating and cooling ducts, electrical conduits, and plumbing piping are then located by knocking out the required areas formed in the core unit I side panels. Following this latter operation,'the cemen- The bottom edge of the piece 30 is provided with a plurality of laterallyspaced, downwardly extending tabs 33, 34, and 35. Successive tabs aredisposed onopposite sides of the reinforcing member 23 of the core unit l3, and thus, retain the lower edge of the piece 30 in assembled relationwith the end ofthe core unit. The coverpiece 30 as well as the partition 27 of the starter unit 29 prevent any cementitious material, while in a flowable state, from dropping through the narrow end of the last or first unit ofa row. v-

Onernethod of erecting the improved deck construction 10 is to first anchor theends of the first elongated support (purlin) l2 to'load-bearing walls, not shown." If

scaffolding is req'u ired, it should be erected so as to .provide the necessary shoring for the supports, A

titious material is distributed over the top surface of the core, units and supports. A'vibratory screed is recom mended to compact the material and to simplify the finishing operation. After the cementitious material has setup for a predetermined length of time, the scaffolding may be removed and, if a finished ceiling (e.g.

acoustical tile) is to be utilized, such may be readily installed on the underside of the deck by employing-wellknown techniques.

The core units, prior to use, may bestored at the job site in a nested relation, as seen in-FIG. 6; In such a nested relation, successive units-are rotatedfl and the enlarged end of each unit'partially overlaps the unit disposed therebeneath. Other ways of stackingor nesting the core units may obviously be. employed, if desired. In forming each cor e='unit,the top panel l4, side panels 15' and base panels 16 may be formed from a pair of like blanks," whichare laminated together. For example, each blank is formed from fiberboard sheet material having a thickness of approximately 0.085 inch. Each blank is preferably prefolded alongfoldlines separating the top panel from'the side panels and the side panels from the base panels. A suitable bonding material is applied between the blanks and then the folded blanks are placed in superposed relation and:

panels willjtend to remain in substantially coplanar relation. By utilizing two blanks of substantially equal thickness, conventional folding and slotting equipment may be employed forming each blank. Furthermore, the fight-back encountered in sheet material of such thickness will not adversely affect the folding and forming of the blanks. Y I

Obviously, other methods'of forming the core units may be employed, if desired. n Thus, it will be seen that an impro'ved deck construction has been provided which can be readily erected, is structurally sound, provides a good tire and sound barrier, and permitsroom partitions or dividers to be readily moved to any desired locations without adverselyaffecting the stability of the deck construction.

- Where the deck construction constitutes a roof, a suitaend flaps extending laterally inwardly 'for one end of said top and side panels and cooperatingwith one another toform a reinforcing flangesubstantially delimiting said member one end, substantially rigid firstreinforcing means provided on said base panels and extendinglongitudinally thereof; elongated substantially rigid second reinforcing means .provided'on' said flange and extending transversely of the longitudinal axis of saidchannel-like member; and elongated substantially rigid third reinforcing means secured to oneendof said side panels and spanning the distance between said base panels, the opposite ends of said third reinforcing means projecting beyond said side panels.

g 2. The core unit of claim 1 wherein each side panel is provided with a locking means disposed adjacent tobut spaced from the end of said unit opposite said reinforcing flange, and the opposite ends of said third reinforcing means extendupwardly from the plane of said base panels and are adapted 'to "interlockingly engage the locking means of a like core unit assembled in'endwise relation therewith. V v I I v H 3J The core unit'of claim2 wherein said locking means comprises transversely aligned open end slots and said base. panels terminate adjacent the slot open ends. I

14.'The core unit of claim 3-wherein' said first reinforcingmeans. are sub'stantially coextensive with said I base panels.'-'

5. The-core unit of. claim 4 wherein .said;firstyreinf rcing means are elongated substantially inflexible strips sec uredto the underside of said base panels the width of each strip being greaterthan the width'of. the base panel-to which itisseciired, each strip having an elongated 'edge'portion projecting laterally from the edge of said base panel adjacent the opposite base panel. f 7'.

. 6. The core unit o'fclaiml wherein said se'cond rein. forcing means has, the ends thereof affixed to the end flapsconnected to said'sidefpanels.

. 8 7. The core unit of claim 1 wherein said-second and third reinforcing means are arranged in spaced, substantially parallel relation. I

8. The core'unit of claim 1 wherein the side panels are provided with knockout areas to permit structural members to be mounted transversely of and extend through: said core unit when said cast in situ deck is constructed. I

9. The core unit of claim 8 wherein said knockout areas can be removed only when a'predeterrnined force is applied thereagainst in one direction. I

10. The core unit of claim 8 whereineach knockout area is delimited on 'onesu'rface of the side panel, by a first line and on the opposite surface of said side panel by'a second line; said lines being disposed in spaced concentric relation. I I

ll. The core unit of claim 10 wherein the. line delimiting the smaller area comprises a cut, penetrating said side panel a distance less than the thickness thereof, and. the line delimiting the larger area corn prises a cut penetrating a distance less than the thickness of said side panel.

r 12'. The core. unit of.claim'10 wherein the line delimiting the smaller area is formed on the surface of the side panel facing angularly downwardly when said unit is horizontally disposed: I

13. The core'unit of claim 1 wherein said top panel and said'side panels are foldably interconnected, and said side panels and said base panels arefoldably interconnected; said panels being formed of blanks bonded to one another in substantially superposed relation.

14. A cast in situ horizontal deck construction comprisinga plurality of elongated supports mounted vhorizontally in uniformly spaced substantially parallel relation, .each support having an upright central portion and shoulders extending laterally from the bottom of said central portion; a plurality of .core units disposed intermediate adjoining supports. and. being vertically supported by the shoulders thereof, the core units disposedintermediate the adjoining supports being arranged in overlapping end-to-end relation'and forming a row; each core unit being formed from. sheet material and having an elongated top panel, a pair of side panels 7 depending outwardly from oppos'ite peripheral portions of said 'top panel, reinforced base panels extending laterally outwardly from the lower edges 'of said side panels and resting upon the shoulders of the adjoining supports, flaps formed at one endof said top panel and the corresponding ends! of said side panels and cooperating with one another to form an inwardly projecting reinforcing'flange substantially delimiting said unit one end,'and,an elongated reinforcing 'means extending "transversely of the. adjoining supports and spanning the distance between the base panelsofa unit, the ends of said reinforcing means projecting I beyond said sidepanels and a stratum of cast in situ cementitious material overlying saicl supports and core units, said stratum having a substantiallyplanar upper surface disposed above said core unit top panels, and beamlike portions depending therefrom anddisposed between adjacent rowsxof core units, each beamlike portion b'eing delimited by the side panels of said adjacent rows of core units and the shoulders of the sup port subtendingsaidside panels, the central portion of said support being embedded in said beamlike portion.

9 15 The deck construction of claim '13 wherein the projecting ends of the transversely extending reinforcadjoining supports, flaps formed on one end of said top panel and the corresponding ends of said side panels ing means of one core unit in a row are in interlocking relation with the opposite end of a second core unit of like constructio'n.

161 The deck construction of claim 14 wherein the side opposite end of said second core unit has the side panels thereof provided with slots which accommodate the rojecting ends of the transversely extending reinforcing means of said one core unit.

17'. The deck construction of claim i4 wherein the end of each core u'nit provided with the, reinforcing flaps is narrower than theopposite 'end of said unit wherebyadjacent core units in a row are in interlocking, partial telescoping relation.

and cooperating with one another to form an inwardly projecting flange, a transversely extending reinforcing means mounted on said starter unit adjacent said projecting flange, and a transversely extending partition fixedly secured to the opposite end of said top and side panels, said partition being providedwith laterally projecting shoulders extending upwardly from the base 18. The deck construction of claim 13 including a starter unit for each row of core units, said starter unit comprising a top panel, a pair of side panels depending outwardly from opposite peripheral portions of said top panel, reinforced base panels extending laterally outwardly from the-lower edges of said, side "panelsland resting upon the shoulders formed adjacent one end of the row.

panels and resting upon the adjacent shoulders of a pair of elongated supports. 7 1 I 19. The deck construction of claim 17 including an end cover piece overlying the inwardly projecting 

1. A core unit for use in constructing a cast in situ horizontal deck or the like, said core unit comprising an elongated channellike member formed from sheet material, said member including an elongated top panel, a pair of elongated side panels depending outwardly from opposite peripheral portions of said top panel, elongated base panels extending laterally outwardly from the lower edges of said side panels, and end flaps extending laterally inwardly for one end of said top and side panels and cooperating with one another to form a reinforcing flange substantially delimiting said member one end, substantially rigid first reinforcing means provided on said base panels and extending longitudinally thereof; elongated substantially rigid second reinforcing means provided on said flange and extending transversely of the longitudinal axis of said channel-like member; and elongated substantially rigid third reinforcing means secured to one end of said side panels and spanning the distance between said base panels, the opposite ends of said third reinforcing means projecting beyond said side panels.
 2. The core unit of claim 1 wherein each side panel is provided with a locking means disposed adjacent to but spaced from the end of said unit opposite said reinforcing flange, and the opposite ends of saId third reinforcing means extend upwardly from the plane of said base panels and are adapted to interlockingly engage the locking means of a like core unit assembled in endwise relation therewith.
 3. The core unit of claim 2 wherein said locking means comprises transversely aligned open end slots and said base panels terminate adjacent the slot open ends.
 4. The core unit of claim 3 wherein said first reinforcing means are substantially coextensive with said base panels.
 5. The core unit of claim 4 wherein said first reinforcing means are elongated substantially inflexible strips secured to the underside of said base panels; the width of each strip being greater than the width of the base panel to which it is secured, each strip having an elongated edge portion projecting laterally from the edge of said base panel adjacent the opposite base panel.
 6. The core unit of claim 1 wherein said second reinforcing means has the ends thereof affixed to the end flaps connected to said side panels.
 7. The core unit of claim 1 wherein said second and third reinforcing means are arranged in spaced, substantially parallel relation.
 8. The core unit of claim 1 wherein the side panels are provided with knockout areas to permit structural members to be mounted transversely of and extend through said core unit when said cast in situ deck is constructed.
 9. The core unit of claim 8 wherein said knockout areas can be removed only when a predetermined force is applied thereagainst in one direction.
 10. The core unit of claim 8 wherein each knockout area is delimited on one surface of the side panel by a first line and on the opposite surface of said side panel by a second line; said lines being disposed in spaced concentric relation.
 11. The core unit of claim 10 wherein the line delimiting the smaller area comprises a cut, penetrating said side panel a distance less than the thickness thereof, and the line delimiting the larger area comprises a cut penetrating a distance less than the thickness of said side panel.
 12. The core unit of claim 10 wherein the line delimiting the smaller area is formed on the surface of the side panel facing angularly downwardly when said unit is horizontally disposed.
 13. The core unit of claim 1 wherein said top panel and said side panels are foldably interconnected, and said side panels and said base panels are foldably interconnected; said panels being formed of blanks bonded to one another in substantially superposed relation.
 14. A cast in situ horizontal deck construction comprising a plurality of elongated supports mounted horizontally in uniformly spaced substantially parallel relation, each support having an upright central portion and shoulders extending laterally from the bottom of said central portion; a plurality of core units disposed intermediate adjoining supports and being vertically supported by the shoulders thereof, the core units disposed intermediate the adjoining supports being arranged in overlapping end-to-end relation and forming a row; each core unit being formed from sheet material and having an elongated top panel, a pair of side panels depending outwardly from opposite peripheral portions of said top panel, reinforced base panels extending laterally outwardly from the lower edges of said side panels and resting upon the shoulders of the adjoining supports, flaps formed at one end of said top panel and the corresponding ends of said side panels and cooperating with one another to form an inwardly projecting reinforcing flange substantially delimiting said unit one end, and an elongated reinforcing means extending transversely of the adjoining supports and spanning the distance between the base panels of a unit, the ends of said reinforcing means projecting beyond said side panels and a stratum of cast in situ cementitious material overlying said supports and core units, said stratum having a substantially planar upper surface disposed above said core unit top panels, and beamlike portions depending tHerefrom and disposed between adjacent rows of core units, each beamlike portion being delimited by the side panels of said adjacent rows of core units and the shoulders of the support subtending said side panels, the central portion of said support being embedded in said beamlike portion.
 15. The deck construction of claim 13 wherein the projecting ends of the transversely extending reinforcing means of one core unit in a row are in interlocking relation with the opposite end of a second core unit of like construction.
 16. The deck construction of claim 14 wherein the side opposite end of said second core unit has the side panels thereof provided with slots which accommodate the projecting ends of the transversely extending reinforcing means of said one core unit.
 17. The deck construction of claim 14 wherein the end of each core unit provided with the reinforcing flaps is narrower than the opposite end of said unit whereby adjacent core units in a row are in interlocking, partial telescoping relation.
 18. The deck construction of claim 13 including a starter unit for each row of core units, said starter unit comprising a top panel, a pair of side panels depending outwardly from opposite peripheral portions of said top panel, reinforced base panels extending laterally outwardly from the lower edges of said side panels and resting upon the shoulders formed adjacent one end of adjoining supports, flaps formed on one end of said top panel and the corresponding ends of said side panels and cooperating with one another to form an inwardly projecting flange, a transversely extending reinforcing means mounted on said starter unit adjacent said projecting flange, and a transversely extending partition fixedly secured to the opposite end of said top and side panels, said partition being provided with laterally projecting shoulders extending upwardly from the base panels and resting upon the adjacent shoulders of a pair of elongated supports.
 19. The deck construction of claim 17 including an end cover piece overlying the inwardly projecting flange formed on the last laid core unit of a row; said piece including a pair of spaced peripheral slits defining a tongue formed along the upper edge thereof and disposed inwardly of said flange, and a plurality of tabs formed along the bottom edge of said cover piece, said tabs resiliently straddling the elongated transversely extending reinforcing means of said last laid core unit of the row. 